Improvement in dredgiwgmmtachihes



- 2 Sheets-Sheet 1.

"W; n. RQBERTSON. DBBDGING MACHINE.

No. 103.373. Patented May 24, 1870.

m: ml: warns on. mow-Luna. WABNIHGTDN. n. c.

' 2 Sheets- Sheet 2. W. D. ROBERTSON. DREDGING MACHINE.

No. 103,373. Patent ed May 24, 1870.

acctswat ailment (Itjiflirr.

WILLIAM B. ROBERTSON, or SAN FRANCISCO, CALIFORNIA;

' Letters PamltNo. 103,373, dated Ma 24, 1870.

.To all whom it n'tay concerm' Be it known that I, WILLIAM D. Ronnnr'sou, of

the city and countyofSan Francisco, State of California, have invented a new and improved Floating Ditching-Machine; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being bad to the accompanying drawings andto the letters marked thereon.

My invention refers to certain improvements in that class of excavating machines used forforming ditches or canals the machinery of which is'placed upon a scow or suitable vessel, and floats upon 'the water when in operatiom-and in which a single scoop isuscd for removing the earth.

The invention consists of certain details of construction hereinafter more fully described.-

In the drawings- Figure 1, sheet 1, is an elevation of a'machine having my improvements.

Figure 2, sheet 1, is a plan of the same, with scoop and scoop-frame removed. Figure-1, sheet 2, is a longitudinal section of scoop and scoop-frame. s

Figure 2, sheet 2, -is a rear elevation of same.

.Figure lfsheet 3, represents a sectional elevation of the circular track, traveling-frame, and a portion of the scoop-frame and Figure 2, sheet. 3, represents a" plan view of the shaft and-gear-wheel, upon which the scoop-flame travels.

To'enable others skilled in the all; or science to V which it most nearly appertains to make and use my invention, I will proceed to describe fully its construction and operation.

a-is the scow, upon which the machinery floats, across which are placed transverse timbers b, projecting beyond the sides of the scow,to which the frame 0 is secured.

d-is the di'iving-shaft, that receives motion ,by means of the pulley e, from a steam-engine, or other motive power, suitably placed abaft the shaft.

The pointed stake-plates fare caused to penetrate the earth on each: side of the ditch by being allowed to drop with the frame 9 from the position shown in fig. 1, sheet I.-

The frame g is'hinged to the racks 9.

The racks are actuated by means of pawls h, which are eccentrically attachedto the main shaft, and receive their motion therefrom. The motion thus communicated to the racks causes the scowto advance forward, through the medium of the frame and'stake-plates, by means of which a hold is secured upon thev bottom of the ditch.

v For the purpose of preventing the racks from being thrown backward by the' return movement of the {mwls h, stopsj are provided, as shown. A suitable ever is also provided,to disconnect the pawl and stop entirely from the racks when it is desired that the boat shall remain stationary.

For drawing'the stake-plates f out of the grounu,

and elevating them to the position shown in sheet 1, fig. 1, and causing the rack g to advance until it comes. in contact with the stops it, the frame I, the chain shives' m, the drums n, andthe chains 0 are. provided.

The'drumsp roll along on each side of the ditch to prevent careening, and should be made larger to. prevent sinking 'into the; ground, and adjustable to correspond to the height of water in the-ditch. These drums should 'also'be constructed in. such a manner that their bouyancy will tend to steady the ma'chine in case the surface of the ground acted upon was entirely Submerged.

The scoop q diflers essentially from all others in beingopen at the back. It is hinged to the scoop-- frame r. This frame is provided with the rack a and guides it, between which the shaft it passes, the bearings of which are secured to the projecting parallel faces of the revolving or oscillating frame.

The frame a is provided with wheels or rollers that run on the circular track w, and is caused to revolve to the right or left about the hollow shaft 10'. by

means of the chains :0 and drums y.

' To the upper end of the scoop-flame r is attached a chain, z, that passes down through the hollow shallw, guided by suitable chain-shives,to the drum-A.

To the shaft 'u is keyed-fast a friction brake-pulley, B, and ratchet-wheel O, and pinion G.

The hereinbefore-described apparatus is providedwith suitable clutch devices, brakes and levers, in

order that it may be properly operated, in the usual well-known manner. I

The operation of the scoop is as follows: By causing the drum A to revolve, the upper endof the scoop-frame is drawn down toward the hollow shaft to, causing the scoop to move forward and upward, passing around the shaft u as a center, filling with earth as it moves, and closing against the back plate E.

When the topof the scoop-ii'amehas thus been drawn down so far as to cause the guide t to pass the horizontal position, it is plain that the weight of the scoop and frame will cause them to slide inboard on the shaft a, rolling on the pinion G.

When this takes place, the drum A is disengaged from the shaft 01, but prevented from revolving by means of the friction-brake F, and the necessary horizont'al movement is then given to the scoop by means .of the revolving or oscillating frame c, which is operated by the chain and pulleys, as before described.

When the scoop has arrived over the desired point, the earth'is discharged by fneans of the rod 1),causing the scoop to tnrn on its hinges, and open a. passage for the earth between the scoop and the back plate E. v

By reversing the motion of the frame ethe scoop and scoop-frame are brought back into a. vertical plane, passing through the next earth or debris to be raised. The hr: he is applied tothe pulley Bto provent'the .shaft a from turning, and. the brake F is thrown ofi, permitting the drum A to revolve and 'slacken the chain z, and allow the scoop-frame to resnmc' a verti-- cal position.

In this position, the rod" 1) being slack, and the forward end of the scoop being the heaviest, that end .lwill be inclined downward ready to penetrate the earth, when we free the pulley B, and allow the scoop and scoop-frame to drop.

.By having the back end of the scoop open the water is allowed to pass through, and thus offer less resistence to the downward passage 0 the scoop. or the operation of filling it witheartln,

A cotter, H, is hinged to the scoop-flame, which,

3. The combination of the orerhanglng frame 0' andthe drums 11, withthc. scow a-, substantially as described.

4. Thecombination of .the stalie-platesf, the frames g ands, the racks g, the pawls h andi, the chains-w,

'drums n, and suitable breaks and levers, with a scow,

as and for the purpose described.

In testimony whereof I have hereunto set myhand and seal. Witnesses: W. D. ROBERTSON. [L. s.'] 0,. W. M. Sm'n x E. V. Some.

ed to drop, cuts the earth in advance- 

